Solar illuminated address sign

ABSTRACT

In one embodiment, an illuminated sign is provided for identifying a geographic aspect. The illuminated sign includes a back plate and at least one symbol. The symbol identifies a geographic aspect. A solar panel is supported with respect to the back plate and includes a solar cell, a rechargeable battery, an activation device, at least one LED, and a control circuit. The control circuit is electrically connected with each of the solar cell, the battery, the activation device, and the LED. The control circuit is configured to detect the presence of sunlight and to facilitate selective recharging of the battery with power from the solar cell when sunlight is present. The control circuit is also configured to selectively provide power to the LED from the battery when sunlight is not present so that the LED will illuminate the symbol when sunlight is not present

RELATED APPLICATION

The present application claims priority of U.S. Provisional ApplicationSer. No. 60/493,771 filed Aug. 11, 2003 and hereby incorporates the sameProvisional Application by reference.

TECHNICAL FIELD

The present invention relates generally to an illuminated sign. Moreparticularly, in one embodiment, the present invention relates to anilluminated sign and circuitry therefor that involves the use of solarenergy to charge rechargeable batteries that are used to selectivelyilluminate one or more geographic identification symbols or othergraphics.

BACKGROUND OF THE INVENTION

Address signs are commonly used to identify certain geographic aspectssuch as addresses for geographic locations such as personal residencesand business establishments, and have been for years. It can bedifficult to locate an address sign at night when there is noillumination. This can be particularly troublesome for emergencypersonnel, service persons, and delivery persons. For example, ambulanceor fire emergency workers can waste valuable life saving seconds or evenminutes searching for an address in the dark.

Conventional illuminated address signs can be expensive and difficult toinstall. In particular, these conventional signs can involve hardwiringa connection with a building's electrical system, which can betime-consuming, messy, troublesome, and expensive to install.Accordingly, there is a need for an illuminated address sign that isinexpensive and simple to install. There is also a need for an addresssign and related circuitry that overcomes the shortcomings of dark housenumbers and existing illuminated address signs. Improved address signcircuitry is also needed for optimizing performance of illuminatedaddress signs.

SUMMARY

Accordingly, one aspect of the present invention provides an illuminatedaddress sign that is inexpensive and simple to install. Another aspectof the present invention provides improved address sign circuitry foroptimizing the performance of illuminated address signs. Yet anotheraspect of the present invention provides an address sign that overcomesthe shortcomings of dark house numbers and existing illuminated addresssigns.

To achieve the foregoing and other aspects, and in accordance with thepurposes of the present invention defined herein, an illuminated signfor identifying a geographic aspect is provided. In one embodiment, theilluminated sign includes a back plate and at least one symbolconfigured for association with the back plate. The symbol can identifya geographic aspect. A solar panel is supported with respect to the backplate and includes a solar cell, at least one rechargeable alkalinebattery, an activation device, at least one LED, and a control circuit.The control circuit is electrically connected with each of the solarcell, the battery, the activation device, and the LED. The controlcircuit is configured to detect the presence of sunlight and is furtherconfigured to facilitate selective recharging of the battery with powerfrom the solar cell when sunlight is present. The control circuit isalso configured to selectively provide power to the LED from the batterywhen sunlight is not present so that the LED will illuminate the symbolwhen sunlight is not present.

In accordance with another exemplary embodiment of the presentinvention, an illuminated sign for identifying a street address of ageographic location is provided. The illuminated sign includes a backplate having a plurality of apertures. Each aperture is configured toreceive a screw for mounting the back plate to a wall. At least onereflective number is configured for association with the back platethrough use of an adhesive whereby the number identifies a streetaddress corresponding to a geographic location. A solar panel isattached to the back plate and includes a solar cell, at least onerechargeable alkaline battery, an activation device, at least one LED,and a control circuit. The activation device comprises at least one of ajumper and a switch. The control circuit is electrically connected witheach of the solar cell, the battery, the activation device, and the LED.The control circuit is configured to detect the presence of sunlight bymonitoring voltage generated by the solar cell. The control circuit isfurther configured to facilitate selective recharging of the batterywith power from the solar cell when sunlight is present. The controlcircuit is also configured to selectively provide power to the LED fromthe battery when sunlight is not present so that the LED will illuminatethe number when sunlight is not present.

In accordance with yet another exemplary embodiment of the presentinvention, an illuminated sign for identifying a street address of ageographic location is provided. The illuminated sign includes a backplate having a plurality of apertures. Each aperture is configured toreceive a screw for mounting the back plate to a wall. At least onenumber is configured for association with the back plate. The numberidentifies a street address corresponding to a geographic location. Asolar panel is attached to the back plate and includes a solar cell, atleast one rechargeable battery, an activation device, at least one LED,and a control circuit. The control circuit is electrically connectedwith each of the solar cell, the battery, the activation device, and theLED. The control circuit includes a switch having a low voltage dropacross its switched terminals as compared to the voltage drop across astandard blocking diode. The switch is configured to selectivelyfacilitate current flow from the solar cell to said battery. The switchis further configured to interrupt the current flow when the voltage ofsaid battery exceeds the voltage produced by the solar cell. The controlcircuit is configured to detect the presence of sunlight by monitoringvoltage generated by the solar cell and is configured to facilitateselective recharging of the battery with power from the solar cell whensunlight is present. The control circuit is also configured toselectively provide power to the LED from the battery when sunlight isnot present so that the LED will illuminate the number when sunlight isnot present.

The present invention as described herein is advantageous for providingan illuminated address sign that is inexpensive and simple to install.The present invention is also advantageous for providing improvedaddress sign circuitry for optimizing performance of illuminated addresssigns. Furthermore, the present invention is advantageous for providingan address sign that overcomes the shortcomings of dark house numbersand existing illuminated address signs. Additional aspects, advantages,and novel features of the invention will be set forth in part in thedescription that follows, and in part will become apparent to thoseskilled in the art upon examination of the following or may be learnedwith the practice of the invention. The aspects and advantages of theinvention may be realized and attained by means of the instrumentalitiesand combinations particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the present invention, it is believed that thesame will be better understood from the following description taken inconjunction with the accompanying drawings in which:

FIG. 1 is a front perspective view depicting an assembled illuminatedsign in accordance with one exemplary embodiment of the presentinvention;

FIG. 2 is an exploded front perspective view depicting the illuminatedsign of FIG. 1 when partially disassembled;

FIG. 3 is a bottom rear perspective view of the solar panel of theilluminated sign of FIGS. 1-2; and

FIG. 4 is a schematic diagram depicting an exemplary electronic circuitfor the illuminated sign of FIGS. 1-3.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

The present invention provides a new illuminated sign, allowing anyone,particularly emergency crew and personnel, to effectively locate anaddress at night. The sign can be totally powered by solar energy andaccordingly does not require the services of an electrician, and caninstead be easily installed by the user. Exemplary embodiments of thepresent invention and its operation are hereinafter described in detailin connection with the views and examples of FIGS. 1-4, wherein likenumbers indicate the same or corresponding elements throughout theviews.

An exemplary illuminated sign 10 of the present invention is shown inFIGS. 1-3 to include a back plate 12, a solar panel 16, and one or moresymbols 14 for identifying a geographic aspect or location. In onetypical embodiment, such a symbol 14 comprises one or more numbers 32(e.g., numbers “8962”) as are typically used to identify a streetaddress corresponding to a geographic location such as a house orbuilding. The symbol(s) or indicia 14 can be formed from any of avariety of materials, although in one embodiment, the symbol(s) 14 maybe formed from a reflective white plastic material (e.g., white plasticpolyethylene).

The symbol(s) 14 can be associated with the back plate 12 in any of avariety of specific manners. For example, as shown in FIGS. 1-2, thesymbols 12 (e.g., numbers 32) can be associated with the back plate 12through use of an adhesive. In particular, the numbers 32 can beattached to an intermediate plate 44 with an adhesive, and theintermediate plate 44 can then be mechanically connected to the backplate 12 (e.g., through a sliding engagement of the intermediate plate44 into grooves 46 of the back plate 12). Alternatively, the symbol(s)14 might instead be directly associated with the back plate 12 throughtheir attachment to the back plate 12 with an adhesive, thus avoidingthe need for any intermediate plate 44. The back plate 12 can therebyserve as a background for the symbol(s) 14. One advantage of having theintermediate plate 44, however, is that the symbol(s) 14 can be moreeasily replaced if ever required (e.g., the intermediate plate 44 havingthe old symbols can be discarded, while the new symbols can be attachedto a new intermediate plate 44 or directly to the back plate 12). Itshould be appreciated, however, that symbol(s) might be associated withthe back plate 12 and/or the intermediate plate 44 in some other mannernot involving adhesives. A template might be provided to assist a userin effectively aligning the symbol(s) with respect to the back plate 12and/or the intermediate plate 44. A reflective border 48 may be providedto surround all of the symbol(s), as shown for example in FIG. 1.Although the border 48 may merely be decorative, the border 48 mightadditionally provide visual confirmation to an onlooker that he or shecan see the entirety of the symbol(s) 14 on a particular sign 10.

The back plate 12 can be configured to be secured with respect to astationary structure. For example, the back plate 12 can include aplurality of apertures (e.g., 28 and 30 shown in FIG. 2) that are eachconfigured to receive a screw for mounting the back plate 12 to anexterior wall of a house or building. As another alternative, the backplate 12 might be configured to connect with a ground stake or aroad-side mailbox.

The solar panel 16 can be supported by the back plate 12 in any of avariety of specific configurations. In one exemplary embodiment, asshown for example in FIGS. 2-3, the solar panel 16 and the back plate 12each comprise interconnecting fastener arrangements 36 and 38, and thesefastener arrangements 36, 38 can facilitate selective attachment of thesolar panel 16 to the back plate 12. In this particular example, thefastener arrangements 36, 38 facilitate sliding engagement of the solarpanel 16 onto the back plate 12, such that the solar panel 16 issupported by the back plate 12, which in turn is supported by a wall, astake, or a mailbox, for example, as discussed above. It should beappreciated that the solar panel 16 might alternatively be attached tothe back plate 12 in any of a variety of other manners (e.g., withfasteners, adhesives, or other such devices).

The solar panel 16 can comprise a top member 40 and a bottom member 42which cooperate to form an enclosure. This enclosure can be adapted tosupport a solar cell 18 (e.g., multi-crystalline 8.4V/200 mA), a controlcircuit (e.g., at least partially inhabiting circuit board 26), one ormore rechargeable batteries 20 (e.g., eight AA 1.5V rechargeablealkaline marketed under the trademark GRANDCELL), one or more LEDs 24(e.g., having a wide viewing angle), and any of a variety of otherelectrical components associated with an exemplary illuminated sign. Asshown in FIG. 3, the top member 40 of the solar panel can have a rearsurface 50 that can selectively interface the back plate 12. The topmember 40 can support a solar cell 18 at an inclined angle with respectto the back plate 12 when the solar panel 16 is attached to the backplate 12 and the back plate 12 is vertically oriented (e.g., as in FIG.1). The top member 40 is designed to hold the solar cell 18 at anglethat allows maximum light gathering. This angle also allows the rain andsnow to slide off and not stick and build up on the solar cell 18.Because of this angle, rain, snow and other debris can simply roll offof the solar panel 16, and can thereby avoid causing any obstruction tothe receipt of sunlight by the solar cell 18.

The bottom member 42 can be selectively removable from the top member40, as shown for example in FIG. 3, in order that a user may access theelectrical components within the solar panel 16 (e.g., to change thebatteries 20). When the solar panel 16 is assembled with the back plate12 (as in FIG. 1), the bottom member 42 can extend outwardly from andabove the symbol(s) 32 so as to provide an overhanging structure, andcan support one or more LEDs 24 (as shown best in FIG. 3). When theilluminated sign 10 is fully assembled, the LEDs 24 can be angled sothat their emitted light can effectively illuminate the symbol(s) 14associated with the back plate 12. For example, the bottom member 42 cansupport the circuit board 26 at twenty-seven degrees below horizontal sothat the reflection of the LEDs 24 connected to the circuit board 26 canbe maximized. In addition to supporting the LEDs 24, the bottom member42 can also support the batteries 20 and at least part of the controlcircuit. As shown in FIG. 2, the control circuit, the batteries, and theLEDs can all be connected to a circuit board 26 that is attached to thebottom member 42 of the solar panel 16. The solar cell 18 can connect tothe circuit board 26 with wires 52. As shown in FIGS. 1-3, the LEDs 24can reside within a recess 56 within the bottom member 42. This recess56 can provide reflective surfaces (e.g., 58 and 60) to help effectivelydirect light from the LEDs 24 to the symbol(s) 14. The bottom member 42might also include vent apertures (e.g., 62) for allowing the escape ofany heat generated by the components within the solar panel 16. One ormore screws (e.g., 64) can be provided to selectively secure the topmember 40 with the bottom member 42. The back plate 12 can also includea ledge 66 that can assist in reflecting light from the LEDs 24 towardthe symbol(s) 14 (while also serving to prevent the intermediate plate44, when present, from sliding out of grooves 46).

The back plate 12 and the solar panel 16 can be formed from any of avariety of materials and using any of a variety of manufacturingtechniques. As one particular example, both the back plate 12 and solarpanel 16 can be formed through injection molding, and can be made ofblack ABS UV plastic. It should be appreciated, however, that the backplate 12 and solar panel 16 need not be formed from similar materialsand/or through similar processes.

Prior to use, an exemplary illuminated sign 10 might be kept in “storagemode.” While in storage mode, the electronics within the solar panel 16are deactivated such that the leakage current drawn from the batteries20 is negligible so that battery storage life is not affected.Accordingly, an illuminated sign 10 can be provided from the factorywith new rechargeable alkaline batteries 20, and those batteries 20 canremain nearly fully charged until a user wishes to actually use theilluminated sign 10. An activation device 22 may be provided to enable auser to select normal operation instead of storage mode. This activationdevice 22 can, for example, comprise a jumper that can be pulled by auser, or alternatively, a switch (e.g., a sliding switch 34) that can betoggled by a user. When the activation device 22 is so engaged by auser, the illuminated sign 10 can begin operation. As depicted in FIG.3, this activation device 22 can be associated with the bottom member 42of the solar panel 16 and can be located proximally to the LEDs 24. Thisplacement can protect the activation device 22 from environmentaldamage, and can help to obscure it from observation by onlookers.

During normal operation of the illuminated sign 10, the solar cell 18gathers solar energy during the day and converts this solar energy toelectrical power. The control circuit then passes this electrical energyto one or more rechargeable alkaline batteries 20 which are therebycharged. The control circuit then detects when sunshine subsides, suchas, for example, by monitoring voltage generated by the solar cell 18(e.g., the control circuit knows that sunshine has subsided by sensingdecreased voltage produced by the solar cell 18). The control circuitthen draws power from the rechargeable alkaline batteries 20 andsupplies this power to one or more LEDs 24. These LEDs provideillumination upon the symbol(s) 14 (e.g., the address numbers 32), andthe symbol(s) 14 can be configured to reflect light generated by theLEDs 24. When sunlight is restored, the control circuit ceases applyingbattery power to the LEDs, and resumes charging of the batteries 20 withpower from the solar cell 18. In this manner, the solar cell 18 assiststhe control circuit in automatically turning on and off the LEDs 24 asneeded to ensure around-the-clock visibility of the symbol(s) 14. Theilluminated sign 10 thereby automatically turns on at dusk and off atsunrise, ensuring illumination when no one is available to manuallyactivate the LEDs 24.

For the illuminated sign 10 to work well over a period of time, thecontrol circuit should be designed so that the power consumed by theLEDs 24 at night can be regenerated during the next day. In oneembodiment of the present invention, four red LEDs (e.g., 24) can beemployed to illuminate the symbol(s) 14 at night, while in anotherembodiment, three white LEDs (not shown in FIG. 2, but depicted in FIG.4 as D5, D6 and D7 and discussed below) can alternatively be employed toilluminate the symbol(s) 14 at night. Other colors and/or quantities ofLEDs might alternatively be provided for illuminating the symbol(s) atnight, provided, however, that their combined power consumption is notexcessive. The LEDs can be selected to consume only a minimal amount ofpower for maximum economy.

For example, if the combined LEDs 24 only draw 8 mA at a selectedoperational voltage from the rechargeable alkaline batteries 20 over anexceptionally long night (e.g., twelve hours), then only 96 mAh would beexpended from the rechargeable alkaline batteries 20. Accordingly, thesolar cell 18 needs only to replenish 96 mAh into the rechargeablealkaline batteries 20, which should be achievable relatively quicklyduring the next day. For example, in a typical case, when eight1.5V/1500 mAh AA batteries are provided in four series of dual-parallelcells, then a total capacity of 3000 mAH at 6V can be available from thebatteries 20 (e.g., as shown in FIG. 4). Consuming only 96 mAh from this3000 mAh source accordingly presents very little load, and shouldtherefore enable the useful lives of the rechargeable alkaline batteries20 to be maximized. Fully charged batteries (e.g., new batteries) canaccordingly provide weeks of operation without any charging. Duringnormal operation of the exemplary illuminated sign 10, no external poweris required, and the illuminated sign 10 is self-contained andmaintenance free.

Rechargeable alkaline batteries have significant advantages for thisapplication as compared to other rechargeable battery types. Forexample, the rechargeable alkaline batteries are stable in extremeweather conditions (cold or heat), have relatively large storagecapacities, and if little current is drawn from them, they can berecharged numerous times (over one-thousand times). As previouslyindicated, only small amounts of energy (e.g., less than 5% of abattery's total charge) could be drawn from such batteries during anormal operational cycle of the illuminated sign 10. Hence, rechargeablealkaline batteries are well suited for use within the illuminated sign10, and can achieve long service periods. Other rechargeable batterytypes might alternatively be employed in some alternate embodiments.

An optional on-board power jack 54 can be provided in association withthe solar panel 16. For example, this jack 54 can be present on the rearsurface 50 of the solar panel 16, as shown in FIG. 3, for example. Thejack 54 can be electrically connected with the control circuit and canbe configured for selective connection to an external wall plug poweradapter. Accordingly, through the jack 54, an external wall plug adapter(e.g., 6 Vdc/200 mA with 2.1 mm plug) can provide power to the controlcircuit. The control circuit can be configured such that this power canbe used to operate the LEDs 24, to assist the solar cell 18 inrecharging the batteries 20, or to recharge the batteries 20 withouthelp from the solar cell 18. However, when the wall plug adapter is soprovided, it should be appreciated that the illuminated sign 10 couldfunction even if the batteries 20 were removed or were no longerchargeable. When the batteries 20 ultimately reach the end of theiruseful lives, they can either be replaced by a user (by removing thelower part of the solar panel), or the external power adapter may thenbe employed as discussed above. In one alternate exemplary mode ofoperation, the illuminated sign 10 can receive power from the externalpower adapter, but can provide continuous illumination from the LEDs 24upon the symbol(s) 14, both day and night. This mode might be selectableby means of a switch or a jumper (e.g., 34), or might otherwise beautomatically selected upon connection of the power adapter with thejack 54.

An exemplary electronic circuit for the illuminated sign 10 of FIGS. 1-3is depicted in FIG. 4, and this circuit can be configured according toadditional aspects of the invention. It should therefore be appreciatedthat any of a variety of alternate circuit configurations might beemployed to achieve the illuminated sign 10 as disclosed and claimedherein. The components and functionality of the exemplary circuit ofFIG. 4 will be appreciated by those skilled in the art, although briefreference will hereafter be provided to certain functionalaspects/components thereof. First, this exemplary circuit includes solarpanel interface components. These components monitor the voltageprovided by the solar cell, and detect the dark threshold (Q3) andcharge threshold (Q7, Q8). These components also include a reverse powerblocking and control switch (Q6), as well as a current limit controlcircuit (Q9, Q10) that limits the current supplied by the solar cell(e.g., to 75 mA±15 mA) to the batteries.

In some solar cell applications, a blocking diode may be provided toprevent leakage currents from escaping from the batteries into the solarcell (e.g., such as can otherwise occur when the solar cell is notcharging the batteries). However, no such blocking diode is provided inthe circuit of FIG. 4. Instead, the circuit of FIG. 4 includes atransistor switch (Q6) that operates to perform the function ofpreventing leakage current, except that the switch (Q6) only absorbs afraction of the voltage drop (across its collector-emitter junction)than would otherwise be absorbed by a similarly situated blocking diode.Hence, the switch (e.g., transistor Q6) can have a low voltage drop(e.g., less than 0.1V) across its switched terminals (e.g., the emitterand collector of Q6) as compared to the voltage drop across a standardblocking diode (e.g., 0.7V). As the solar cell must produce enoughvoltage above this voltage drop to charge the batteries, it has beenfound that a lower-voltage solar cell can thus be provided when atransistor switch (Q6) is used in lieu of a blocking diode (as in FIG.4).

The switch (Q6) of FIG. 4 is also shown to be configured to selectivelyfacilitate current flow from the solar cell to the battery. Moreparticularly, the switch (Q6) can be configured to substantiallycompletely interrupt the current flow between the solar cell and thebatteries when the voltage of the batteries exceeds the voltage producedby the solar cell (as described above to prevent leakage currents).Also, the switch (Q6) can be used to modulate or otherwise variablyadjust the amount of power that is allowed to pass to the batteries. Inthis manner, the switch (Q6) can limit the amount of current that ispassed from the solar cell to the batteries (and to the shuntregulators, as described below).

Other components are provided to drive the LEDs. For example, certain ofthese components provide LED current control and temperaturecompensation (e.g., transistors Q1, Q2, Q19). This exemplary circuitalso includes power adapter interface components that detect when poweris present (e.g., resistor R43) so that shunt protection can be providedfor the batteries. Also, this circuit provides components (e.g.,resistor R4) to detect a missing plug (indicative of storage mode) andto disable biasing (e.g., transistor Q15), thereby deactivating allcircuits. This circuit also includes a resistor network for providing acurrent limiting function (R36, R37, R39, R40, R41).

Other components within this exemplary circuit are provided to protectthe rechargeable alkaline batteries (BAT1, BAT2, BAT3, BAT4, BAT5, BAT6,BAT7, and BAT8). For example, shunt regulator components (U1, U2, U3,U4) are provided independently for each battery to limit theend-of-charge voltage to 1.65V, and to thereby prevent overcharging.Shunt regulator components (U1, U2, U3, U4) can be selected to have alow leakage current and to not be prone to temperature variations, andso that they may be suitable for preventing the battery voltage frombeing exceeded (e.g., are able to maintain a 1.65V maximum voltageacross each cell). Transistors (Q5, Q11, Q12, Q13, Q14) switch theprotection circuits on only when needed (e.g., charging voltage higherthan battery voltage) in order to minimize leakage current. Hence, thecontrol circuit of FIG. 4 includes shunt regulator circuits forprotecting the batteries from being overcharged. However, the shuntregulator circuit is also configured to absorb substantially no leakagecurrent at all times except during charging, as will be appreciated bythose skilled in the art.

If the voltage of the rechargeable alkaline batteries is allowed todiminish beyond a particular threshold, the batteries will bepermanently damaged. Accordingly, a circuit for an illuminated signmight incorporate components to prevent the voltage of the rechargeablealkaline batteries from being diminished below this threshold. Forexample, the LEDs can be selected such that their operational voltage isjust above the threshold voltage of the combined battery arrangement. Insuch a configuration, the LEDs can simply shut off (and thereby stopconsuming power) before the threshold voltage of the batteries isreached. Other alternative protection arrangements might otherwise beprovided.

If the illuminated sign is constructed for use without any externalpower adapter, the components shown in the “Version B” area on theschematic of FIG. 4 need not be populated. If the power adapter optionis provided, then the components shown in the “Version A” area on theschematic of FIG. 4 need not be populated, and the battery can bedisabled when nothing is plugged into the power adapter jack (J2).Accordingly, components can be provided in the circuit to accommodate anexternal power adapter. Also, the schematic of FIG. 4 includes both redLEDs (D1, D2, D3, and D4) and white LEDs (D5, D6, and D7), although itshould be appreciated that an exemplary illuminated sign might onlyinclude either the red LEDs (D1, D2, D3, and D4) or the white LEDs (D5,D6, and D7).

In addition to the aforementioned “storage mode”, an illuminated sign inaccordance with the teachings of the present invention can have twooperating modes, namely a “solar panel mode” and a “power adapter mode”.In the solar panel mode, the batteries can be charged during the day,and can then supply power to the LEDs at night. New batteries canprovide up to two months operation without any charging. No poweradapter is required, and the unit is self-contained and maintenance freeuntil the batteries need replacement (e.g., typically after a few yearsof operation). In power adapter mode, when the power adapter isconnected, the LEDs can illuminate continuously both day and night. Inthis configuration, the batteries and solar panel are not required to beoperational or even present, although if the batteries are present, theycan be continuously charged and maintained at the end-of-charge voltageso that they can provide backup during power outages (e.g., up to twomonths). Alternatively, in power adapter mode, an illuminated sign canbe configured to turn the LEDs off during the day, in which case thesolar cell serves as a photo-detector.

Methods of operating an illuminated sign should also be appreciated. Forexample, such a method might include the step of detecting the voltageproduced by a solar cell. If that voltage is below a first threshold,LEDs can be illuminated. When the solar cell voltage exceeds the firstthreshold and exceeds a second threshold (e.g., the combined batteryvoltage), power from the solar cell can be passed to the batteries forrecharging the batteries. If the solar cell voltage exceeds the firstthreshold but does not exceed the second threshold, then no power ispassed from the solar cell to the batteries and the LEDs are notilluminated. The method might also include the step of detecting theconnection of a power adapter, and might, upon such detection,continuously illuminate the LEDs. Also, the method might, in response tomovement of a jumper or a switch, deactivate the circuit tosubstantially prevent leakage (e.g., in storage mode). It should also beappreciated that an exemplary method might incorporate any of a varietyof other steps as will be appreciated by those skilled in the art uponreading the disclosure herein.

Although the illustrative illuminated signs specifically described aboverelate to address signs for homes and businesses, it should beappreciated that other illuminated signs in accordance with theteachings of the present invention might be provided for use in otherapplications. For example, an exemplary illuminated sign might beprovided at a road intersection to identify a street name, at amunicipal boundary to identify a city name, or for any other suchapplication in which a geographic marker would benefit from selectiveillumination.

The foregoing description of exemplary embodiments and examples of theinvention has been presented for purposes of illustration anddescription. It is not intended to be exhaustive or limit the inventionto the forms described. Numerous modifications are possible in light ofthe above teachings. Some of those modifications have been discussed,and others will be understood by those skilled in the art. Theembodiments were chosen and described in order to best illustrate theprinciples of the invention and various embodiments as are suited to theparticular use contemplated. It is hereby intended that the scope of theinvention be defined by the claims appended hereto.

1. An illuminated sign for identifying a geographic aspect, the systemcomprising: a back plate; at least one symbol configured for associationwith the back plate, said symbol identifying a geographic aspect; asolar panel being supported with respect to the back plate, the solarpanel comprising a solar cell, at least one rechargeable alkalinebattery, an activation device, at least one LED, and a control circuit,the control circuit being electrically connected with each of the solarcell, said battery, the activation device, and said LED; wherein thecontrol circuit is configured to detect the presence of sunlight, isconfigured to facilitate selective recharging of said battery with powerfrom the solar cell when sunlight is present, and is configured toselectively provide power to said LED from said battery when sunlight isnot present so that said LED will illuminate said symbol when sunlightis not present.
 2. The illuminated sign of claim 1 wherein the backplate includes a plurality of apertures, each aperture being configuredto receive a screw for mounting the back plate to a wall.
 3. Theilluminated sign of claim 1 wherein the solar panel is supported by theback plate.
 4. The illuminated sign of claim 1 wherein said symbol isassociated with the back plate through use of an adhesive.
 5. Theilluminated sign of claim 1 wherein said symbol is configured to reflectlight generated by the LED.
 6. The illuminated sign of claim 1 whereinsaid symbol comprises at least one number.
 7. The illuminated sign ofclaim 1 wherein the solar panel further comprises a power jack beingelectrically connected with the control circuit and being configured forselective connection to an external wall plug power adapter.
 8. Theilluminated sign of claim 1 wherein the activation device comprises atleast one of a jumper and a switch.
 9. The illuminated sign of claim 1wherein the control circuit detects the presence of sunlight bymonitoring voltage generated by the solar cell.
 10. The illuminated signof claim 1 wherein the control circuit includes a switch having a lowvoltage drop across its switched terminals as compared to the voltagedrop across a standard blocking diode, the switch being configured toselectively facilitate current flow from the solar cell to said battery,the switch being further configured to interrupt said current flow whenthe voltage of said battery exceeds the voltage produced by the solarcell.
 11. The illuminated sign of claim 10 wherein the switch comprisesa transistor.
 12. The illuminated sign of claim 1 wherein the controlcircuit includes means for selectively facilitating current flow fromthe solar cell to said battery.
 13. The illuminated sign of claim 1wherein the control circuit includes a shunt regulator circuit forprotecting said battery from being overcharged, the shunt regulatorcircuit being configured to absorb substantially no leakage current atall times except during charging.
 14. The illuminated sign of claim 1wherein the control circuit further comprises shunt regulator means forprotecting said battery from being overcharged.
 15. The illuminated signof claim 14 wherein the control circuit further comprises currentlimiting means for limiting the amount of current passed from the solarcell to said battery and to the shunt regulator means.
 16. Theilluminated sign of claim 1 wherein the solar panel and the back plateeach comprise interconnecting fastener arrangements, whereby saidfastener arrangements facilitate selective attachment of the solar panelto the back plate.
 17. The illuminated sign of claim 16 whereby saidfastener arrangements facilitate sliding engagement of the solar panelonto the back plate.
 18. The illuminated sign of claim 1 wherein thesolar panel comprises a top member and a bottom member, the top membersupporting the solar cell and the bottom member supporting said LED. 19.The illuminated sign of claim 18 wherein the bottom member furthersupports said battery and at least part of the control circuit.
 20. Theilluminated sign of claim 18 wherein the bottom member is selectivelyremovable from the top member.
 21. The illuminated sign of claim 1wherein said symbol identifies a street address corresponding to ageographic location.
 22. An illuminated sign for identifying a streetaddress of a geographic location, the system comprising: a back plateincluding a plurality of apertures, each aperture being configured toreceive a screw for mounting the back plate to a wall; at least onereflective number configured for association with the back plate throughuse of an adhesive, said number identifying a street addresscorresponding to a geographic location; a solar panel attached to theback plate, the solar panel comprising a solar cell, at least onerechargeable alkaline battery, an activation device, at least one LED,and a control circuit, the activation device comprising at least one ofa jumper and a switch, the control circuit being electrically connectedwith each of the solar cell, said battery, the activation device, andsaid LED; wherein the control circuit is configured to detect thepresence of sunlight by monitoring voltage generated by the solar cell,is configured to facilitate selective recharging of said battery withpower from the solar cell when sunlight is present, and is configured toselectively provide power to said LED from said battery when sunlight isnot present so that said LED will illuminate said number when sunlightis not present.
 23. The illuminated sign of claim 22 wherein the solarpanel further comprises a power jack being electrically connected withthe control circuit and being configured for selective connection to anexternal wall plug power adapter.
 24. The illuminated sign of claim 22wherein the control circuit includes a switch having a low voltage dropacross its switched terminals as compared to the voltage drop across astandard blocking diode, the switch being configured to selectivelyfacilitate current flow from the solar cell to said battery, the switchbeing further configured to interrupt said current flow when the voltageof said battery exceeds the voltage produced by the solar cell.
 25. Theilluminated sign of claim 22 wherein the control circuit includes ashunt regulator circuit for protecting said battery from beingovercharged, the shunt regulator circuit being configured to absorbsubstantially no leakage current at all times except during charging.26. An illuminated sign for identifying a street address of a geographiclocation, the system comprising: a back plate including a plurality ofapertures, each aperture being configured to receive a screw formounting the back plate to a wall; at least one number configured forassociation with the back plate, said number identifying a streetaddress corresponding to a geographic location; a solar panel attachedto the back plate, the solar panel comprising a solar cell, at least onerechargeable battery, an activation device, at least one LED, and acontrol circuit, the control circuit being electrically connected witheach of the solar cell, said battery, the activation device, and saidLED, the control circuit including a switch having a low voltage dropacross its switched terminals as compared to the voltage drop across astandard blocking diode, the switch being configured to selectivelyfacilitate current flow from the solar cell to said battery, the switchbeing further configured to interrupt said current flow when the voltageof said battery exceeds the voltage produced by the solar cell; whereinthe control circuit is configured to detect the presence of sunlight bymonitoring voltage generated by the solar cell, is configured tofacilitate selective recharging of said battery with power from thesolar cell when sunlight is present, and is configured to selectivelyprovide power to said LED from said battery when sunlight is not presentso that said LED will illuminate said number when sunlight is notpresent.